M.Sc Thesis


M.Sc StudentSeri Yaniv
SubjectAssessment of Load Bearing Capabilities of CFRP Filament
Wound Structures
DepartmentDepartment of Aerospace Engineering
Supervisor ASSOCIATE PROF. Haim Abramovich
Full Thesis textFull thesis text - English Version


Abstract

Correct estimation of load bearing capabilities and prediction of failure has an important role in the design and quality control of filament wound (FW) composite fiber reinforced plastic (CFRP) structures, such as composite overlapped pressure vessels, filament wound pipes and other. Such structures are widely used in aerospace, military and gas industries and must provide safe operation.

There is a limited number of studies and methods that are used today for assessment of load bearing capabilities of FW CFRP structures. The present research is intended to review the state-of-the-art practices, assist in the development of a new approach for evaluation of structural integrity of filament wound structures at loads below those normally applied during proof testing, and improve operational safety of CFRP pressure equipment.

During the present study, we have tested and analyzed NOL rings, a parallel filament wound hoop test specimens, for identification of characteristic stages of damage accumulation and development using experimentally measured characteristics of acoustic emission (AE), strain and displacement. A correlation between fracture loads and different parameters of AE was observed. It was also shown that acoustic emission technology could detect effectively matrix micro cracking, fiber breakage and other damage mechanisms related to CFRP damage. The test results of the NOL rings and full-scale products showed similarity in fracture properties including stages of damage accumulation and developing and were experimentally confirmed by acoustic emission and strain measurements.